This invention relates to telecommunication systems and, more specifically, to generating timing signals for such systems.
In telecommunication networks or systems, data or a data stream is transported from one location in the network to another location in the network at various data rates. Typically, the data is transported between locations based on some synchronized or timed event. Thus, there is a need to have an accurate timing mechanism that is in phase with other timing sources in the system. Occasionally, the situation arises wherein the timing mechanism fails and the timing signal is lost temporarily. Eventually, the timing signal is restored, however, when the timing device is restored, it is typically not synchronized or in phase with other timing sources.
Known solutions include complex and expensive circuitry to ensure that a timing signal is not lost. Thus, in the event that the source of the timing signal is lost, circuitry acts as the timing source and generates a timing signal so that the system is not subject to phase problems due to lost and later restored timing signals. However, as indicated these solutions are costly and expensive. Additionally, such solutions typically are a temporary solution until the timing source for the timing signal can be restored.
Therefore, what is needed is a system and method for restoring and phase aligning two timing signals in the event that the source for one timing signal is lost temporarily and later restored or switched to another signal.